One poll finding this week that shook Democrats came in a survey conducted by Democracy Corps, a consortium organized by party consultants Stan Greenberg, Al Quinlan and James Carville. It asked voters to pick two from a list of seven problems that explain “why the country is going in the wrong direction.”

The survey found that among independent voters, 40 percent — by far the largest group — picked this option: “Our borders have been left unprotected and illegal immigration is growing.”

I have argued for a long time that the problem both parties face is not the regularization of the 12 to 20 million illegal aliens inside the U.S., but seriousness about border security. Neither party is serious about the border, and both parties pay a price for this fecklessness.

Contrast the desultory progress on the 370 miles of border fence authorized in 2006 (of which less than 75 new miles have been built, and most of that not the double-fencing that most Americans expect) with the urgent effort to reconstruct Minnesota’s collapsed bridge. I am in the Twin Cities this morning, and the front page story in the Pioneer Press is headlined “Feds earmark an additional $123.5 million for 35W span.” A related story on the rebuilding effort begins:

Rest is for those with time to spare, and Peter Sanderson doesn’t have any.

The project manager on the Interstate 35W bridge rebuilding project said there won’t be much downtime if the Minneapolis span is to be up and running by Christmas 2008. For the foreseeable future, crews will spend 20 hours a day, six days a week on the job, and rest only on Sunday.

“We’re very confident that we can meet the timeline of December 24,” Sanderson told reporters Thursday at a kickoff event to highlight the start of the reconstruction.

The 35W bridge matters to people, so work is underway, on a schedule, with designs in place a goal to be reached.

Compare that with Secretary Chertoff’s recent progress report on the border fencing given on my show: Few details, no urgency, no promises beyond the most general, and that undermined by a caution about Congressional funding.

The good news is that both of the serious GOP candidates are committed to the border fencing, and the issue will be a feature of the 2008 race. Rudy Giuliani and Mitt Romney are both smart enough to detail their plans for border security again and again, and those plans include the fence.

Democrats would be wise to listen to Dionne and get behind the fence, pushing the funding through in this Congress along with demands for rapid completion of construction according to a detailed schedule. The Pelosi-Reid Democrats will never do that, and Hillary will try and avoid the issue.

The GOP should talk about the fence at every opportunity, and it would be a very good thing if the Bush Administration would give them something to talk about.